1. Field of the Invention
The present invention relates to a system for distributing video contents from a distribution server to a user's display terminal through a transmission path and, more particularly, to a contents distribution system for distributing contents to such a display terminal whose display unit is small as a portable communication terminal, a distribution server and a display terminal thereof, and a contents distribution program.
2. Description of the Related Art
FIG. 13 is a block diagram showing a structure of a conventional video distribution system, in which a video distribution server 60 for distributing video distributes video contents through a transmission path 30 and a user's video display terminal 70 receives and presents the video contents.
Japanese Patent Laying-Open (Kokai) No. 2000-32441 proposes a technique of extracting telop information from television broadcasting received by a television receiver and transmitting and displaying the information to and on a still picture display terminal such as a remote-controlled terminal, thereby exhibiting character information to have high quality.
Since telop information often contains such important information for understanding stories and contents at the time of viewing and listening to video as telop in a news program and telop information including superimposition of a movie, it is effective to present the information to users by using high-quality images easy to read.
Although not included in the above-described conventional techniques, extraction of not only telop information but also other character information than telop is useful which exists in common scenes such as a product name written on a product shown in a commercial film, characters on a signboard and a mark in the background of a drama.
Although the above-described conventional art disclosed in Japanese Patent Laying-Open (Kokai) No. 2000-324416 targets common television broadcasting, the recent speed-up of the Internet, speed-up of radio communication in particular, enables users to view accumulated video clips such as film advertisement and music promotion video through a PC at home or a mobile phone used outdoors. Distribution of live video is also conducted by distributing video taken by a camera called Web camera which is disposed at a sightseeing spot or on a road through the Internet.
Although distributing such video without modification needs a communication path of an extremely wide band, image compression and coding techniques enable reduction of the amount of information. With the Internet whose band is approximately 64 kbps, for example, viewing video can be realized by distributing compressed video and decoding the same by a terminal having received it.
For transmitting video at a bit rate as low as 64 kbps, however, video is coded with its resolution reduced or its quality degraded and then transmitted to a portable terminal or a PC at home. Thus reducing the resolution or degrading image quality results in making character information contained in the video unclear to be extremely hard to read.
As described above, character information includes information crucial for video viewing, so that when the character information becomes hard to read, it might hinder video viewing.
As described in the foregoing, the conventional art has the following problems.
There have conventionally existed no technique of, at the time of distributing video contents at a low bit rate, extracting character information including telop information, coding the information to have high quality, distributing the coded information and having a user's terminal display the same. The conventional art disclosed in Japanese Patent Laying-Open (Kokai) No. 2000-324416, for example, extracts telop from common television broadcasting received, while it fails to extract telop from video contents reproduced by a portable communication terminal or the like and distributed at a low bit rate because characters are distributed being unclear.